How far a raft will sink in water

Given:
raft consists of 4 sealed barrels laying on their sides with demensions of 21 in. diameter, 3 ft. in length, and weighing 30 lbs. each. The barrels are attached by a wooden deck weighing 179 lbs.
find:
how far does the raft sink below the waters surface
with a specific weight of the water being 62.38 lb./cubic foot.

I tried to figure this out by setting up a ratio of the specific weights but found out that since the barrels are on their sides this does not work. Really stumped by this one???